Hi gbm,I like your bot, thanks for sharing your projectI have tried using servo motors without success My bot was definitly too heavy (to much inertia) for the small servosServos are slow (60 RPM), large wheels is a plus to get an acceptable linear speedPlease let me have a link to the servos you used

So, what do we get sofar ?? a noisy Acc angle and a drifting Gyro rate of rotationLet's fuse them !!!I have tried 2 filtering technologies:

- Complementary filterThis filter is rather easy to understandI have seen several successfull implementation using complementary filtersI tried it and got mixed results, probably due to some non related design flawsMore details here: http://web.mit.edu/scolton/www/filter.pdf

- Kalman filterWell over normal understanding , but... efficient Please see http://tom.pycke.be/mav/71/kalman-filtering-of-imu-datamore details at http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1282384853/15 (Reply #24)I modified a code snippet I found on the Web to produce an easy to use/self contained function see http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1282384853/0 (Reply #14)

When rotating the board, make sure that GYRO_rate has the right sign:GYRO_rate should be positive when rotating board toward +256 Quids (+180°)and negative when rotating board toward -256 Quids (-180°)This is another pitfall (been there, done that )

The smoothing effect is quite impressive and is best viewed in graphing packages such as Processing or LabView

Watch it here http://www.youtube.com/v/H5Drlqv1t3s?The red line is the raw ACC angle, the blue one is the filtered Signal

hi there , I have trouble searching for motors like yours. what are the factors that led you to choose this motor? I need to find a substitute but I do not know what to look out for. and they are rather expensive.